VM: Fix an app-jit related shutdown race.

runtime/bin/isolate_data.cc

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/isolate_data.h"
 #include "bin/snapshot_utils.h"
 
 namespace dart {
 namespace bin {
 
@@ skipping 11 matching lines @@
       dependencies_(NULL) {
   if (package_root != NULL) {
     ASSERT(packages_file == NULL);
     this->package_root = strdup(package_root);
   } else if (packages_file != NULL) {
     this->packages_file = strdup(packages_file);
   }
 }
 
 
+void IsolateData::OnIsolateShutdown() {
+  if (builtin_lib_ != NULL) {
+    Dart_DeletePersistentHandle(builtin_lib_);
+    builtin_lib_ = NULL;
+  }
+}
+
+
 IsolateData::~IsolateData() {
   free(script_url);
   script_url = NULL;
   free(package_root);
   package_root = NULL;
   free(packages_file);
   packages_file = NULL;
   free(udp_receive_buffer);
   udp_receive_buffer = NULL;
-  if (builtin_lib_ != NULL) {
-    Dart_DeletePersistentHandle(builtin_lib_);
-  }
   delete app_snapshot_;
   app_snapshot_ = NULL;
 }
 
 }  // namespace bin
 }  // namespace dart